A hard drive may be provided with a cache for the hard drive, typically found in random access memory (RAM), to cache data that has been read from the hard drive. However, because the hard drive cache is located in the RAM, data which is to be written to the hard drive is unable to be cached in the cache of the hard drive, because if the computer system were to fail the data to be written to the hard drive would be lost due to the loss of power to the RAM.
In addition, for mobile computers, repeatedly accessing the hard drive is a power consuming activity that involves a power management policy that attempts to reduce the frequency of spinning up the hard drive and the continued use of the hard drive. For example, common run time power management on operating systems for hard drives, consists of, if the hard drive doesn't receive requests in X minutes, the hard drive spins down.